A laser energy measuring device and method based on heat balance type water direct absorption

Abstract

The present application relates to a kind of based on heat balance type water direct absorption laser energy measuring device and method, mainly solve the problem that existing laser measuring device cannot be satisfied with smaller volume structure while, realize high-energy laser long time, high-precision measurement. Including cooling device, cavity front shell and cavity rear shell respectively connected to the two ends of cooling device;Cavity front shell is provided with window;Cooling device includes multiple thermoelectric piles, cooling parts, connecting ring, sealing element, water inlet pipe, water outlet pipe;Multiple cooling parts and connecting ring are spaced apart along front and back direction, and connecting ring is arranged between adjacent two cooling parts;First cooling part is connected with cavity front shell along front and back direction, and last cooling part is connected with cavity rear shell;Thermoelectric pile is arranged at both ends of cooling part respectively;Cooling part is provided with water channel, sealing element is sleeved on the circumferential side of corresponding cooling part, water inlet pipe and water outlet pipe are connected with the water channel in corresponding cooling part, and the other end is connected with external cold water machine.

Description

Technical Field

[0001] The present invention relates to a laser energy measurement device and method, and in particular to a laser energy measurement device and method based on thermal balance type water direct absorption. Background Art

[0002] Power / energy is a key metric for high-energy laser systems and is typically measured. As laser power and energy continue to increase, so too do measurement methods. Compared to conventional lasers, high-energy lasers possess significant destructive power, posing significant measurement challenges. Furthermore, the lack of a standard calibration source for high-power lasers requires more complex physical and chemical processes to be involved in the measurement process, increasing the sources of measurement uncertainty and thus raising concerns about measurement accuracy.

[0003] The existing laser power / energy measurement methods include indirect measurement technology and direct measurement technology; (1) Indirect measurement technology mainly obtains power / energy based on the laser after sampling the measurement part, mainly including spectroscopic sampling method, CCD imaging method, array detection method, etc.; The disadvantages of indirect measurement technology include: First, indirect measurement uses large-rate attenuation, which can reach thousands to tens of thousands of times. On the one hand, the attenuation multiple is difficult to determine accurately, and on the other hand, the measurement accuracy of weak signals is limited, resulting in low reliability of the final result, and therefore it is usually not used as a laser power / energy identification method; second, the attenuation component is easily damaged under high-power / energy laser irradiation; (2) Direct measurement technology mainly includes passive absorption type and active absorption type; the passive absorption type measurement method uses Solid materials (such as copper, graphite, etc.) are processed into special structures (such as reflection cones, integrating spheres, etc.) to absorb energy, and the temperature change is calculated to determine the laser energy. This is limited by the thermal conductivity and damage threshold of the solid material itself. At the same time, the heat exchange rate of the material is relatively low. When the energy and power of the laser are high, the surface of the material will be damaged due to excessive temperature, so it is not suitable for measuring high-power and high-energy lasers; the active absorption type uses water or other substances as a cooling medium to convert the incident laser into water temperature or other temperature, and determines the laser energy by calculating the temperature rise, which greatly improves the upper limit of measurement; the main disadvantage is that the measured laser power / energy is low due to the limited water in the cavity and slow heat dissipation, which is not suitable for high-power / energy laser measurement.

[0004] In summary, existing laser energy measurement devices cannot achieve long-term, high-precision measurement of high-energy lasers while meeting the requirements of a small volume structure. Summary of the Invention

[0005] The purpose of the present invention is to solve the technical problem that existing laser energy measurement devices cannot achieve long-term and high-precision measurement of high-energy lasers while meeting the requirements of a small volume structure, and to provide a laser energy measurement device and method based on thermal balance type water direct absorption.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A laser energy measurement device based on thermal balance type water direct absorption is special in that it includes a cooling device, and a cavity front shell and a cavity rear shell respectively connected to the two ends of the cooling device;

[0008] The front end of the cavity front shell is provided with a window for incident laser to be measured;

[0009] The cooling device includes a plurality of thermopiles, a plurality of cooling parts, a plurality of connecting rings, a plurality of sealing members, a plurality of water inlet pipes, and a plurality of water outlet pipes;

[0010] The plurality of cooling parts and the plurality of connecting rings are coaxially arranged along the front-to-back direction. The plurality of cooling parts are arranged sequentially along the front-to-back direction with a gap between two adjacent cooling parts. The plurality of connecting rings are respectively arranged between two adjacent cooling parts and connected to the cooling parts. The end of the first cooling part along the front-to-back direction is connected to the other end of the cavity front shell, and the end of the last cooling part is connected to the end of the cavity rear shell.

[0011] A thermopile is provided at each end of the cooling component for measuring the temperature at the corresponding position of the cooling component; a water channel is provided along the circumferential direction of the cooling component, and multiple water inlet pipes, water outlet pipes, and sealing members are provided in a one-to-one correspondence with the multiple cooling components, and the sealing members are mounted on the circumference of the corresponding cooling components to seal the water channel so that it is in a closed space; one end of the water inlet pipe and the water outlet pipe are respectively connected to the water channel in the corresponding cooling component, and the other end is used to connect to the output end and input end of the external chiller, respectively;

[0012] The cavity in the front shell of the cavity, the multiple cooling parts and the inner circle of the connecting ring, and the cavity in the rear shell of the cavity are connected in sequence to form a cavity for storing water.

[0013] Furthermore, a water inlet is provided on the front shell of the cavity, and a water outlet is provided on the rear shell of the cavity;

[0014] An input pipe, an output pipe and a water pump are also provided;

[0015] One end of the input pipe is connected to the water inlet, and the other end is connected to the output end of the water pump; one end of the output pipe is connected to the water outlet, and the other end is connected to the input end of the water pump.

[0016] Furthermore, valves are provided at the water inlet and the water outlet.

[0017] Furthermore, the water channel is a spiral structure;

[0018] One end of the water inlet pipe is communicated with the spiral inlet of the water channel, and one end of the water outlet pipe is communicated with the spiral outlet of the water channel.

[0019] Furthermore, the window includes a window body and an incident plate;

[0020] The window body is connected to the front end of the cavity front shell;

[0021] The window body is provided with a mounting groove adapted to the incident plate, the incident plate is installed in the mounting groove, and the laser to be measured is incident into the cavity through the incident plate.

[0022] Furthermore, the window body is connected to the cavity front shell by bolts, and a sealing gasket is provided at the connection;

[0023] The window body is made of stainless steel, and the incident plate is made of quartz glass.

[0024] Furthermore, the cavity front shell, cavity rear shell, cooling parts, and connecting ring are all made of copper;

[0025] The material of the thermopile is graphite.

[0026] Furthermore, the cooling component and the adapter ring are interference fit;

[0027] The cavity front shell and the cavity rear shell are respectively interference-fitted with corresponding cooling parts.

[0028] At the same time, the present invention also provides a laser energy measurement method based on direct absorption of thermal equilibrium water, based on a laser measurement device based on direct absorption of thermal equilibrium water, which is special in that it includes the following steps:

[0029] Step 1: Measure the temperature of corresponding positions through multiple thermopiles at both ends of the cooling part, take the average of the temperatures measured by all thermopiles as the initial temperature T1, and record it;

[0030] Step 2: The laser to be measured is incident into the cavity through the window. The water in the cavity absorbs the laser energy and converts it into thermal energy of the water.

[0031] During the process of water heat energy transfer in the front-to-back direction, cooling water is continuously supplied to the water channel through an external chiller, so that the temperature of the cooling water in the water channel is always at a stable value;

[0032] Step 3: When the temperature measured by the thermopile is observed to be stable, thermal equilibrium is reached. The temperature at the corresponding position is measured in real time by the thermopiles at both ends of each cooling part. The average temperature measured by all thermopiles is taken as the measured temperature T2 and recorded.

[0033] Step 4: Calculate the heat flow Φ;

[0034]

[0035] Where: A is the sum of the internal surface areas of multiple cooling parts, in m 2 ; λ is the thermal conductivity of the cooling part, in W / (m*K); T is the temperature rise, in °C, T=T2-T1; x is the length of the cooling part in the front-to-back direction, in m; q is the heat flux, in W / m 2 ;

[0036] Step 5: The value of the heat flux Φ obtained is equal to the value of the laser power, completing the measurement of the laser power / energy.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The present invention absorbs laser light through the water in the cavity, converts the laser energy into water temperature, and continuously removes heat through cooling water, so that the device can absorb more laser energy while using a smaller volume of water. This makes the device not only smaller in size but also capable of achieving longer-term and higher-power laser measurements. At the same time, by arranging thermopiles at both ends of each cooling part, the temperature at different positions can be measured in real time. Compared with temperature measurement at the water outlet and water inlet, this temperature measurement method has a smaller measurement error, thereby improving the accuracy of measuring laser power / energy.

[0039] 2. The water pump provided in the present invention can further accelerate the flow rate of water in the cavity, thereby accelerating the heat exchange efficiency between the water in the cavity and the cooling water, thereby further improving the heat absorption capacity of the device and increasing the upper limit of the measurement of laser power / energy and time.

[0040] 3. The present invention provides a spiral water channel structure, which can increase the contact area between cooling water and cooling parts, thereby improving heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic structural diagram of an embodiment of a laser energy measurement device based on thermal balance type water direct absorption according to the present invention;

[0042] Figure 2 It is a schematic structural diagram of a cooling device in an embodiment of a laser energy measurement device based on heat balance type water direct absorption of the present invention.

[0043] In the picture:

[0044] 1- cavity front shell, 2- cavity back shell;

[0045] 3-cooling device, 31-thermopile, 32-cooling parts, 33-connecting ring, 34-water inlet pipe, 35-water outlet pipe, 36-sealing element;

[0046] 4-window, 41-window body, 42-incident plate;

[0047] 5- cavity, 6- water channel, 7- water inlet, 8- water outlet, 9- input pipe, 10- output pipe, 11- water pump, 12- valve. DETAILED DESCRIPTION

[0048] To further clarify the objectives, advantages, and features of the present invention, the following, in conjunction with the accompanying drawings and specific embodiments, further describes in detail the laser energy measurement device and method based on direct absorption of heat-equilibrium water. The advantages and features of the present invention will become more apparent through the following detailed description. It should be noted that the drawings are highly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the objectives of the embodiments of the present invention. Furthermore, the structures shown in the drawings are often portions of actual structures.

[0049] The “front and back” directions mentioned in the article are the same as those in the attached Figure 1 The "left-right" direction on paper.

[0050] like Figure 1 As shown, the present invention is a laser energy measurement device based on thermal balance type water direct absorption, including a cooling device 3, and a cavity front shell 1 and a cavity rear shell 2 respectively connected to the two ends of the cooling device 3, wherein the cavity front shell 1 and the cavity rear shell 2 are both made of copper.

[0051] A window 4 for the laser to be measured is provided at the front end of the cavity front shell 1; the window 4 includes a window body 41 and an incident plate 42; the window body 41 is connected to the front end of the cavity front shell 1; a mounting groove adapted to the incident plate 42 is provided on the window body 41, and the incident plate 42 is installed in the mounting groove, and the incident plate 42 and the window body 41 form a flat sealing surface, so as to facilitate the laser to be measured to pass through the incident plate 42 and enter the cavity 5; in a preferred embodiment of the present invention, the window body 41 is connected to the cavity front shell 1 by bolts, and a sealing gasket is provided at the connection to perform a sealing function; the material of the window body 41 is stainless steel, and the material of the incident plate 42 is quartz glass. In other embodiments of the present invention, the material of the incident plate 42, the material of the window body 41 and the connection method of the window body 41 and the cavity front shell 1 can also be adaptively adjusted according to specific needs.

[0052] The cooling device 3 includes a plurality of thermopiles 31, a plurality of cooling parts 32, a plurality of connecting rings 33, a plurality of sealing members 36, a plurality of water inlet pipes 34, and a plurality of water outlet pipes 35; wherein the cooling parts 32 and the connecting rings 33 are both made of copper; the specific number of cooling parts 32 can be specifically designed according to the size of the laser energy. The higher the laser energy, the more corresponding cooling parts 32 are, and the more water in the cavity 5 can be used to absorb the laser energy; the cooling parts 32 and the connecting rings 33 are both annular structures, and the wall thickness of the cooling parts 32 is greater than the wall thickness of the connecting rings 33; the plurality of cooling parts 32 and the plurality of connecting rings 33 are coaxially arranged along the front and rear directions, and the plurality of cooling parts 32 are arranged along the front and rear directions. They are arranged in sequence in the rear direction and there is a gap between two adjacent cooling parts. Multiple connecting rings 33 are respectively arranged between two adjacent cooling parts 32 and connected to the cooling parts 32; the end of the first cooling part 32 in the front-to-back direction is connected to the other end of the front shell 1 of the cavity 5, and the end of the last cooling part 32 is connected to the end of the rear shell 2 of the cavity 5; in a preferred embodiment of the present invention, in order to prevent the heat transfer problem caused by the connection of connecting parts (bolts, etc.), the cooling parts 32 and the connecting rings 33 are designed to adopt an interference fit, and the front shell 1 of the cavity and the rear shell 2 of the cavity are respectively interference fit with the corresponding cooling parts 32, which not only solves the heat transfer problem but also makes the connection effect more reliable.

[0053] The cavity in the front shell 1 of the cavity, the cavity in multiple cooling parts 32 and the connecting ring 33, and the cavity in the rear shell 2 of the cavity are connected in sequence to form a cavity 5 for storing water; a thermopile 31 is provided at each end of the cooling part 32 for measuring the temperature at the corresponding position of the cooling part 32, and the material of the thermopile 31 is graphite.

[0054] The cooling part 32 is provided with a water channel 6 along the circumferential direction. Figure 2 As shown, the water channel 6 is a spiral structure; multiple water inlet pipes 34, seals 36, and water outlet pipes 35 are respectively arranged in one-to-one correspondence with multiple cooling parts 32, and a seal 36 is mounted on the circumference of the corresponding cooling part 32 to seal the water channel 6 on the corresponding cooling part 32 so that it is in a closed space; the seal 36 is made of stainless steel. In a preferred embodiment of the present invention, an insulating layer can also be provided on the seal 36 to reduce the heat dissipation of water; one end of a water inlet pipe 34 is connected to the spiral inlet of the water channel 6 in the corresponding cooling part 32, and one end of the water outlet pipe 35 is connected to the spiral outlet of the water channel 6. The other ends of the water inlet pipe 34 and the water outlet pipe 35 are respectively used to connect to the output end and input end of the external chiller.

[0055] In a preferred embodiment of the present invention, a water inlet 7 is provided on the cavity front shell 1, and a water outlet 8 is provided on the cavity rear shell 2; in this embodiment, the water inlet 7 and the water outlet 8 are respectively provided on the peripheral sides of the cavity front shell 1 and the cavity rear shell 2, and in other embodiments of the present invention, they can also be provided at the ends of the cavity front shell 1 and the cavity rear shell 2; an input pipe 9, an output pipe 10 and a water pump 11 are also provided; one end of the input pipe 9 is connected to the water inlet 7, and the other end is connected to the output end of the water pump 11; one end of the output pipe 10 is connected to the water outlet 8, and the other end is connected to the input end of the water pump 11. The water pump 11 is provided to quickly output the water in the cavity 5 through the water outlet 8 and input through the water inlet 7, which can accelerate the water flow rate in the cavity 5, thereby improving the heat dissipation efficiency of the water.

[0056] In a preferred embodiment of the present invention, valves 12 are provided at both the water inlet 7 and the water outlet 8 , which not only have a sealing effect but also can adjust the flow rate at the water inlet 7 and the water outlet 8 .

[0057] In this device, heat loss mainly includes heat conduction from the body, heat conduction from the water to the window 4, and radiation heat transfer from the water to the space through the window 4. However, due to the following reasons: First, the thermal conductivity of glass is much lower than that of copper, so the heat loss in this part is relatively small; second, although the temperature rise of the water is about 60 degrees Celsius, the heat transfer is concentrated in the cooling device 3, so the external radiation heat transfer is relatively small; therefore, the heat loss of this device is relatively small.

[0058] The present invention provides a laser energy measurement method based on thermal equilibrium type water direct absorption, based on a laser energy measurement device based on thermal equilibrium type water direct absorption, comprising the following steps:

[0059] Step 1: Measure the temperature of corresponding positions through multiple thermopiles 31 at both ends of the cooling part 32, take the average of the temperatures measured by all thermopiles 31 as the initial temperature T1, and record it;

[0060] Step 2: The laser to be measured is incident into the cavity 5 through the window 4. The water in the cavity 5 absorbs the laser energy and converts the laser energy into heat energy of the water.

[0061] During the process of water heat energy being transferred in the front-to-back direction, cooling water is continuously supplied to the water channel 6 through an external chiller, so that the temperature of the cooling water in the water channel 6 is always kept at a stable value;

[0062] Step 3: When the temperature measured by the thermopiles 31 is observed to be stable, thermal equilibrium is reached. The temperatures at the corresponding positions are measured in real time by the thermopiles 31 at both ends of each cooling component 32. The average of the temperatures measured by all the thermopiles 31 is taken as the measured temperature T2 and recorded.

[0063] Step 4: Calculate the heat flow Φ;

[0064]

[0065] Where: A is the sum of the internal surface areas of the multiple cooling parts 32, in m 2 ; λ is the thermal conductivity of the cooling part 32, in W / (m*K); T is the temperature rise, in °C, T=T2-T1; x is the length of the cooling part 32 in the front-to-back direction, in m; q is the heat flux density, in W / m 2 ;

[0066] Step 5. Heat flux is the amount of heat passing through a given area per unit time. When laser irradiation occurs, water absorbs laser energy. Theoretically, water can absorb all the total energy of laser irradiation without any heat loss. Therefore, the laser power / energy that this device can measure depends on the heat transfer and heat dissipation conditions within the device. That is, the thermal conductivity formula can be used as the calculation formula for laser power. In other words, the value of the heat flux Φ obtained is equal to the value of the laser power, completing the measurement of laser power / energy.

[0067] The actual calculation results are as follows: For copper, the thermal conductivity is 400W / (m*K), the area A of a cooling part 32 is the internal contact area, the inner diameter of the cooling part 32 is 200mm, the length is 25mm, and the thickness is 25mm. To deviate the temperature from the distance, and to prevent the water temperature from being too high and causing phase change, the water temperature can be set from a normal temperature of 20 degrees Celsius to about 80 degrees Celsius, that is, the laser power that can be cooled by a cooling component 32 is:

[0068]

[0069] Assuming that the device is designed with 14 cooling parts 32, the calculation results are as follows:

[0070]

[0071] The total length of the cooling device 3 is the length of the 14 cooling parts 32 plus the length of the connecting ring 33, that is, the calculation result:

[0072] l=0.025·14+0.006·13=0.428m;

[0073] Consult the literature to calculate how much laser energy can be measured by existing cyclic active absorption type;

[0074] Pt=mC△T;

[0075] Among them, P represents power, t represents time, m represents the mass of water, C represents the specific heat capacity of water, and △T represents temperature rise.

[0076] According to the calculation result, the cavity size is 200mm in diameter and approximately 400mm in length, the density of water is 1000kg / m 3 , the specific heat capacity of water is 4200J / (kg·℃), the mass of water is calculated as 12.566kg by the formula m=ρv, and the temperature rise of water is 60℃; it is found through the experiment on the fixed mass water type direct absorption device that the water temperature can rise to 60℃ only after 180s of laser irradiation, and the calculation result is 17592.919W.

[0077] It can be found through comparison that the fixed mass water type direct absorption device with similar size can absorb less laser energy, so the laser measuring device of the present application has better effect than the prior art.

Claims

1. A laser energy measurement device based on thermal equilibrium type water direct absorption, characterized by: It comprises a cooling device (3), and a cavity front shell (1) and a cavity rear shell (2) respectively connected to two ends of the cooling device (3); The front end of the cavity front shell (1) is provided with a window (4) for incident laser light to be measured; The cooling device (3) includes a plurality of thermopiles (31), a plurality of cooling parts (32), a plurality of connecting rings (33), a plurality of sealing members (36), a plurality of water inlet pipes (34), and a plurality of water outlet pipes (35); The plurality of cooling parts (32) and the plurality of connecting rings (33) are coaxially arranged along the front-to-back direction, the plurality of cooling parts (32) are sequentially arranged along the front-to-back direction and a gap is provided between two adjacent cooling parts (32), and the plurality of connecting rings (33) are respectively arranged between two adjacent cooling parts (32) and connected to the cooling parts (32); the end of the first cooling part (32) along the front-to-back direction is connected to the other end of the cavity front shell (1), and the end of the last cooling part (32) is connected to the end of the cavity rear shell (2); A thermopile (31) is provided at each end of the cooling part (32) for measuring the temperature at a corresponding position of the cooling part (32); a water channel (6) is provided on the circumferential side of the cooling part (32) along the circumferential direction; a plurality of water inlet pipes (34), water outlet pipes (35), and sealing members (36) are provided in one-to-one correspondence with the plurality of cooling parts (32), and the sealing members (36) are fitted on the circumferential side of the corresponding cooling part (32) for sealing the water channel (6) so that the water channel (6) is in a closed space; one end of the water inlet pipe (34) and the water outlet pipe (35) are respectively connected to the water channel (6) in the corresponding cooling part (32), and the other end is respectively used to be connected to the output end and the input end of an external chiller; The water channel (6) is a spiral structure; One end of the water inlet pipe (34) is connected to the spiral inlet of the water channel (6), and one end of the water outlet pipe (35) is connected to the spiral outlet of the water channel (6); The cavity front shell (1) is provided with a water inlet (7), and the cavity rear shell (2) is provided with a water outlet (8); An input pipe (9), an output pipe (10) and a water pump (11) are also provided; One end of the input pipe (9) is connected to the water inlet (7), and the other end is connected to the output end of the water pump (11); one end of the output pipe (10) is connected to the water outlet (8), and the other end is connected to the input end of the water pump (11); The cavity in the cavity front shell (1), the inner ring of the plurality of cooling parts (32) and the connecting ring (33), and the cavity in the cavity rear shell (2) are sequentially connected to form a cavity (5) for storing water.

2. The laser energy measurement device based on thermal balance type water direct absorption according to claim 1, characterized in that: Valves (12) are provided at the water inlet (7) and the water outlet (8).

3. A laser energy measurement device based on thermal balance type water direct absorption according to claim 1 or 2, characterized in that: The window (4) comprises a window body (41) and an incident plate (42); The window body (41) is connected to the front end of the cavity front shell (1); The window body (41) is provided with a mounting groove adapted to the incident plate (42), the incident plate (42) is mounted in the mounting groove, and the laser to be measured is incident into the cavity (5) through the incident plate (42).

4. The laser energy measurement device based on thermal balance type water direct absorption according to claim 3, characterized in that: The window body (41) is connected to the cavity front shell (1) via bolts, and a sealing gasket is provided at the connection; The material of the window body (41) is stainless steel, and the material of the incident plate (42) is quartz glass.

5. The laser energy measurement device based on thermal balance type water direct absorption according to claim 4, characterized in that: The cavity front shell (1), cavity rear shell (2), cooling component (32), and connecting ring (33) are all made of copper; The material of the thermopile (31) is graphite.

6. The laser energy measurement device based on thermal balance type water direct absorption according to claim 5, characterized in that: The cooling part (32) and the connecting ring (33) are interference fit; The cavity front shell (1) and the cavity rear shell (2) are respectively interference-fitted with corresponding cooling parts (32).

7. A method for measuring laser energy based on direct absorption of thermally balanced water, based on a laser energy measuring device based on direct absorption of thermally balanced water according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: measuring the temperature of corresponding positions through multiple thermopiles (31) at both ends of the cooling parts (32), taking the average value of the temperatures measured by all thermopiles (31) as the initial temperature T1, and recording it; Step 2: The laser to be measured is incident into the cavity (5) through the window (4), and the water in the cavity (5) absorbs the laser energy and converts the laser energy into heat energy of the water; During the process of transferring the heat energy of the water in the front-to-back direction, the water channel (6) is continuously supplied with cooling water by an external chiller, so that the temperature of the cooling water in the water channel (6) is always at a stable value; Step 3: When the temperature measured by the thermopile (31) is observed to be stable, thermal equilibrium is reached, and the temperature of the corresponding position is measured by the thermopile (31) at both ends of each cooling part (32), and the average value of the temperatures measured by all the thermopiles (31) is taken as the measured temperature T2 and recorded; Step 4: Calculate the heat flow Φ; Where: A is the sum of the internal surface areas of multiple cooling parts (32), in m 2 ; λ is the thermal conductivity of the cooling part (32), the unit is W / (m*K); T is the temperature rise, the unit is ℃, T=T2-T1; x is the length of the cooling part (32) in the front-to-back direction, the unit is m; q is the heat flux in W / m 2 ; Step 5: The value of the heat flux Φ obtained is equal to the value of the laser power, completing the measurement of the laser power / energy.

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